Explosive pumping and dredging method and apparatus

ABSTRACT

A method and apparatus particularly suited for underwater dredging, trenching and the like. An explosion chamber is provided with a fuel source, a fuel ignitor and an exhaust outlet. A dreg intake conduit having a check valve communicates with the explosion chamber as does a dreg exhaust chamber. Material to be dredged enters the dreg intake and fills the explosion chamber to a certain level while fuel is admitted to the explosion chamber. The fuel is burned or exploded which closes the check valve in the dreg intake and forces the dreg material out through the exhaust conduit.

FIPYEill United StatesPatent 1191 I Wood 1 Jan. 22, 1974 1 EXPLOSIVEPUMPING AND DREDGING 1,257,217 2/1913 Griffith 417/75 METHQD ANDAPPARATUS 1,867,478 7/1932 Stelzner "137/5253 [75] Inventor: Charles D.Wood, San Antonio, Tex. Primary Examiner Al Lawrence Smith [73]Assignee: Southwest Research Institute, Bexar, Assistant m ichard E- GuCk T Attorney, Agent, or Firm-James F. Weiler et a1.

[22] Filed: June 29, 1972 [57] ABSTRACT [21] PP N04 2671602 A method andapparatus particularly suited for underv water dredging, trenching andthe like. An explosion [52] US. Cl 417/74, 37/58, 37/195, chamber isProvided with a fuel Source, a fuel ignitof 4 417/900 and an exhaustoutlet. A dreg intake conduit having a 511 1111. C1 ..F04r1/16, E02f3/88 check valvc communicates with the explosionlcham- 581 Field ofSearch 417/73, 74, 75, 900; 37/58, her as does a dreg exhaust chamber-Material to be 37 59; 60/22] dredged enters the dreg intake and fillsthe explosion chamber to a certain level while fuel is admitted to 5Reta-wees Cited the explosion chamber. The fuel is burned or explodedUNITED STATES PATENTS which closes the check valve in the dreg intakeand l 027 430 5/1912 P t 7/74 forces the dreg material out through theexhaust conoore e a 671,600 4/1901 Kurtz 417/74 1,069,772 8/1913Drummond 417/74 9 Claims, 12 Drawing Figures F IGNITION E- 2825 5, MRACTIVATING MEANS 24b L.

W -///7//9// /K -//7 //F F PATENIEUJANZZIBM SHEET 1 BF 3 FIG. 2

I Pmmmmzzwm SHEET 2 [1F 3 6 Q SOURCE OF IGNITION FUEL AND AIR ACTIVATINGMEANS FIG. 5

PATENTED JAN 2 2 I974 FIG. Io

FIG. I

FIG; I2

VIELOCITY OF FLUID COM BUSTION SHEET 3 BF 3 20 I 'u E (1. o. Z

' TIME SECONDS s K. I v I "A"*- B -I---'----(;. N m l 3200- 0') LLI 0:CL

lOO- LLI m g I r-- 5 I l A o 2 4 6 8 IO TIME SECONDS I U) 2 8 .J f g In! 0 I l 2 4 6 w 8 TIME SECONDS EXPLOSIVE PUMPING AND DREDGING METHOD-AND APPARATUS A BACKGROUND OF THE INVENTION The method and apparatus ofthe present invention make use of an internal combustion or explosivepumping technique. Internal combustion pumps and related propulsiondevices are known in the art as illus trated by U.S. Pat. Nos. 368,678,1,093,669, 1,152,394, 1,157,071, 1,158,303, 1,257,217, 2,272,477,3,202,108, 2,885,988, and 3,494,317.

Prior internal combustion type pumps or propulsion devices have hadnumerous drawbacks. For example, internal combustion pumps have sufferedthe disadvantage of interrupted flow due in large part to reciprocatingtype operation involving a plurality of cycles. In addition, certain ofthe prior art devices have been operable only by balancing columns ofwater in a U- shaped configuration pump inherently involving delicateoperation.

By and large, prior internal combustion type pumps and related deviceshave been able to pump or function only with respect to liquids due inlarge part to the use of check valves requiring positive closure inorder to operate properly. Consequently, such devices are not suitablefor pumping solid-liquid slurries since solid materials tend to clog themoving parts of the pump resulting in malfunction of the system.

It would, therefore, be advantageous to provide an improved internalcombustion type pump that provides uninterrupted flow without the use ofa check valve on the discharge side of the pump and which is capable ofpumping even solid-liquid slurries such as material dredged from lakebeds, sea beds and the like. The present invention is directed to such adevice uniquely adapted to function as a dredge as will be explained.

SUMMARY OF THE INVENTION The present invention relates to a method andapparatus for underwater dredging and particularly the preparation oftrenches in river beds, lake beds, sea beds, or the like. An explosionchamber is provided to which is attached a dreg intake conduit and adreg exhaust conduit. A check valve is located within the dreg intakeconduit for limiting flow of fluid or dreg slurry unidirectionally tothe explosion chamber. The system of apparatus functions by admittingdregs to the explosion chamber by way of the dreg intake conduit. Dregsrise to a certain level within the explosion chamber while fuel is beingadmitted into the chamber. At a predetermined time, the fuel is ignitedand the force of the combustion thrusts the dreg material or slurrythrough the dreg exhaust conduit. The same force momentarily closes thecheck valve in the dreg intake conduit so that the dreg material isforced through the exhaust conduit. The exhaust gases from thecombustion reaction pass through the exhaust outlet in the combustionchamber and the cycle is repeated. It should be noted that the inertiaof the liquid in the exhaust conduit produced by the gas pressure issufficient to maintain the flow of liquid throughout the cycle.

It is, therefore, an object of the present invention to provide a uniqueinternal combustion or explosion type apparatus useful as a pump forsolid-liquid slurrles.

Another object of the present invention is the provision of suchapparatus for dredging underwater beds and particularly for formingtrenches in underwater beds.

It is a further object of the present invention to provide a method forexplosively pumping fluids without interruption of flow, the processbeing uniquely adapted to pump or move solid-liquid mixtures or slurriessuch as dredged materials.

Yet a further object of the present invention is the provision of adredging apparatus having an explosion chamber with a fuel inlet,ignition means and an exhaust outlet as well as a dreg intake conduitprovided with a check valve and a dreg exhaust conduit.

Other and further objects, features and advantages will be apparent fromthe following description of the presently preferred embodiment of theinvention given for the purpose of disclosure and taken in conjunctionwith the accompanying drawings.

DESCRIPTION OF THE DRAWINGS In the drawings forming a part of thedisclosure herein, like character references designate like partsthroughout the several views, wherein,

FIG. 1 is a side elevational view, partly in cross section, of aninternal combustion device according to the present invention,

FIG. 2 is a similar view showing the combustion chamber of the devicecontaining dregs or material to be pumped at the time fuel within thecombustion chamber is ignited,

FIG. 3 is a similar view wherein the dreg material has been forced outthe dreg exhaust conduit after ignition and exhaust gases are passingout the exhaust outlet means while a fuel mixture is entering thecombustion chamber, r

FIG. 4 is a similar view showing the dreg material again rising withinthe combustion chamber for repetition of the cycle,

FIG. 5 is a side elevational view of thee dredging apparatus accordingto the present invention,

FIG. 6 is a plan view taken along the line 6-6 of FIG. 5,

FIG. 7 is a partial side elevational view, partly in cross section, of afurther embodiment of the dredging apparatus according to the presentinvention uniquely suited for preparing an underwater trench,

FIG. 8 is a front elevational view, taken along the line 8-8 of FIG. 7,

FIG. 9 is a view of the check valve means within the dreg intake conduittaken along the line 9-9 of FIG. 7, and

FIGS. 10, 11 and 12 are graphic representations of an example accordingto the present invention wherein are plotted velocity of fluid,combustion chamber pressure and total flow of fluid versus time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. I, aninternal combustion system 10 is shown having an explosion chamber 12generally of an elongated dome configuration oriented in the verticalplane with upper and lower portions. The explosion chamber 12 isprovided with a fuel inlet supply means I4 for providing an explosivemixture of fuel to thechamber 12. The chamber is further provided withan ignition means 16 for exploding fuel within the chamber in timedrelation with the fuel inlet supply means 14. An exhaust outlet means I8removes exhaust gases from the explosion chamber 12 in timed relationwith the fuel inlet supply means 14 as well as the ignition means 16.

A dreg intake conduit is in fluid communication with the lower interiorportion of the explosion chamber 12 and has secured therewithin a checkvalve means 22 for limiting flow of fluid through the conduit 20unidirectionally to the explosion chamber 12. Also in fluidcommunication with the lower interior portion of the explosion chamber12 is a dreg exhaust conduit 24.

As shown in FIGS. 2-4, the fuel inlet supply means 14 preferablycomprises a fuel conduit 26 in fluid communication with the upperinterior portion of the explosion chamber 12. A check valve 28 issecured within the fuel conduit 26 to limit flow of fuelunidirectionally to the explosion chamber. As will be recognized bythose skilled in the art, any suitable form of check valve 28 may beemployed, although the drawings illustrate use of a simple ball-typecheck valve wherein a ball 30 is forced against a seat 32 to close theconduit 26 to further entry of fuel. In the open position, the ball 30may rest against retention. lugs 34 to allow fuel to pass around theball and into the chamber 12.

The ignition means 16 shown in FIGS. 1-4 may be any suitable means forigniting the fuel mixture within the chamber 12 as may be selected bythose skilled in the art. For example, the ignition means I6 may takethe form of a high voltage spark plug connected to a suitable electricalsource. Preferably, means are provided which coact with the check valve28 within the fuel conduit 26 to sense closure of the check valve 28 andactivate the ignition means I6. Again, such means may be selected bythose skilled in the art and may take the form, for example, of anelectrical switch which is closed when the ball 30 engages the seat 32of the check valve 28 to close an electrical circuit thereby providingcurrent to the ignition means I6 or spark plug to are or spark forpurposes of igniting the fuel within the chamber.

With reference to FIG. I (and also as shown in FIGS. 2-4) the exhaustoutlet means 18 comprises an exhaust gas conduit 36 in fluidcommunication with the inter-' ior portion of the explosion chamber 12at a point juxtaposed but just above a plane between the intake conduit20 and the exhaust conduit 24 as shown in the drawings. A float valvemeans 38 is affixed to the exhaust gas conduit 36 in order that theexhaust conduit 36 may open to the interior of the explosion chamber toremove exhaust gases upon lowering of the level of dreg material withinthe chamber 12 and for closing the exhaust gas conduit 36 upon rising ofthe level of dreg material within the 'chamber.

While any suitable float valve means 38 may be employed, the preferredarrangement as shown in the drawings includes a ball member 40 havingbuoyancy relative to the dreg material entering the explosion chamberI2. A seat 42 is affixed to the exhaust gas conduit 36 within theexhaust chamber 12. A cage member 44 is secured-to the exhaust gasconduit re straining the ball member 40 for releasable engagement withthe seat 42. The cage member 44 may be suitable wire mesh or the like ofsufficient strength to withstand the force of combustion within thechamber 12 yet having openings therewithin so as to admit thesolid-liquid slurry or dreg material to cause the ball member 40 tofloat into engagement with the seat 42. An advantage of use of the floattype valve means 38 is that the valve closes before the dreg materialbeing pumped has an opportunity to wedge between the ball 40 and theseat 42 thereby preventing cloggage that might otherwise cause amalfunction of the system.

Turning now to the embodiment of FIGS. 5 and 6, the internal combustionapparatus I0 is shown having a dreg intake conduit 20 with a flaredmouth 20a which is adapted for suction of dregs or other material to bedredged. In addition, the dreg exhaust conduit 24 is provided with anupwardly extending portion 24a which in turn divides into a Y shapedconfiguration with conduit arms 24b and 24c. The upward extendingportion 24a adapts the system for dredging while the conduit arms 24band 24c in the Y shaped configuration further adapts the dreg exhaustconduit for digging trenches and the like. Thus, effluent from thedredging operation is moved upward and outward to either side of atrench or channel that is being dug with the apparatus.

Referring now to the embodiment of FIGS. 7, 8 and 9, the internalcombustion device 10 of the present invention is illustrated with amodified flared inlet for the dreg intake conduit 20, this embodimentbeing especially preferred for digging large trenches or channels inunderwater bodies of earth. Thus, the dreg intake conduit 20 is providedwith pronounced flared or outwardly tapered walls 46 wherein the openingor leading edge 48 may be of a circumference or periphery approximatingthe size of the trench to be dredged.

With reference to FIG. 9, there is shown a view of the check valve means22 secured within the intake conduit 20. The check valve means includesa grid member 52 secured within the dreg intake conduit and an openablecover member 54 secured against the side of the grid member 52 facingthe explosion chamber 12. While the openable cover member 54 may beformed of any suitable material and in any suitable configuration, onepreferred embodiment as shown is a plurality of sectors 56 forming thecover 54, each sector 56 being openable and overlapping another sectoron one radial edge if desired. It will be seen that the sectors 56 ofthe cover 54 rest against the grid 52 when fluid pressure from theexplosion chamber-l2 is applied against the cover 54. Otherwise, thesegments 56 of the cover 54 open to admit dreg material from the I mouthof the intake conduit 20.

Referring to FIGS. 7 and 8, a grate 50 is secured within the dreg intakeconduit on the side of the check valve grid member 52 opposed from theexplosion chamber 12. The grate 50 is provided with openings smallerthan the openings within the grid member 52 of the check valve 22 to actas a filter to screen out or break up agglomerated or larger materialsthat would otherwise tend to clog or plug the grid member 52 of thecheck valve 22.

In operation and with reference particularly to FIGS. 2, 3 and 4 of thedrawings, the system of the present invention may be partially ortotally submerged as required. The depth of submersion, however, must beat least that of the level indicated by the reference numeral 60. In anyevent, the mouth (20a of FIG. 5 or 48 of FIG. 7) of the intake conduit20 is submerged to contact the bed of material to be dredged.

At the beginning of a cycle of operation, the fuel mixture inlet valveI4 is closed. the exhaust valve 38 is closed, and the chamber is filledwith liquid. The closure of the valve I4 activates the ignition means l6and the mixture of fuel and air burns within the chamber 12 so that thepressure of the mixture increases preferably about sixfold. Thispressure must exceed pressure of the fluid outside of the chamber I2.Since the gas pressure is higher than the outside fluid or liquidpressure, the check valve 22 closes and liquid is forced out the dregexhaust conduit 24. The expansion of the burnt gas continues pushingliquid out of the pipe 24, the liquid level in the chamber 12 falls, andfinally the gas exhaust valve 38 is uncovered. Pressure of thecombustionproduct gases in the chamber at this point should be greater than oneatmosphere which is accomplished by regulating the amount of combustiblefuel admitted to the chamber 12 just before ignition and by placingoutlet 38 preferably within the lower half of the chamber 12 so that theburnt gases do not escape immediately upon ignition. The outlet end ofthe exhaust pipe 36 should be above water level in the air, i.e., at apressure of about one atmosphere. Thus, since the exhaust gases are at apressure higher than one atmosphere, the burnt gases flow out theexhaust pipe 36. I

The exhaust valve 38 is acted on by a number of. forces when in theclosed position. Atmospheric pressure P acts on the ball 40 in adownward direction in an area equal to the inside cross-sectional areaof the exhaust pipe 36. The gas pressure P acts on all areas of the ballnot covered by the exhaust pipe 36, and the net pressure acts in anupward direction on an area equal in size to the inside cross-sectionalarea of the exhaust pipe 36. The weight (w) of the ball 40 acts in adownward direction. The force balance therefore is:

(where A is the area equal-to the inside cross sectional area of thepipe) in order for the valve to open.

Since (where D is ball diameter and p is ball density), the

equation can be rewritten:

P,,A+(1rDI6)(p)-P,A

(Pf u) (1P4) D 16 (p) a 0 D 16 (p) 2 (PM (P,,- P,,) where d is theinside diameter of the exhaust gas conduit 36.

As the burnt gases flow out the pipe 36 to the surface of the body beingpumped or dredged, pressure in the chamber I2 decreases. When thechamber pressure decreases to pressure of the fuel/air mixture in theinlet pipe 26, the fuel/air inlet valve [4 opens and fresh fuel mixtureflows into the chamber. Since the liquid in the dreg exhaust conduit 24has been accelerated to a considerable velocity during the fuelexpansion, it continues to 'flow even after the exhaust valve 38 opens.

When the exhaust outlet valve 38 opens and reduces the chamber pressureto one atmosphere, the dreg inlet check valve 22 opens due to theoutside water or fluid pressure and liq-uid flows into the chamber I2.

6 The inflow of liquid eventually exceeds the outflow of liquid (sincethe latter is slowing down) and the level of liquid in the chamber 12begins to rise. Outflow of liquid continues, however, but at a steadilydecreasing rate. When the liquid level reaches the exhaust valve 38, itcloses.

To close, buoyancy of the ball must be positive: 5 (91. P) 3 0 (where pliquid density) This equation, plus the last equation derived above,give the requirements for design of the valve 38 as will be understoodby those skilled in the art.

When the exhaust outlet valve 38 closes, pressure in the chamber I2 isone atmosphere. The external water pressure continues to force liquidthrough the dreg inlet valve 22 and into the chamber 12. Momentum of thecolumn of water in the outlet pipe 24 is still sufficient to maintainoutward flow in this pipe, albeit at everdecreasing rates, and theliquid level rises past the valve 38. As it does, pressure in thechamber 12 begins to increase above one atmosphere. The air/fuel mixturepressure should be higher than one atmosphere such as by use of an aircompressor forcing air down the'fuel mixture inlet pipe I4 so that thefuel/air mixture continues to enter the chamber I2 as the liquid levelrises therein. The pressure of the fuel/air mixture 2 is controlled aswill now be appreciated such that it IS less than the water pressure sothat eventually the rising level of liquid in the chamber 12 compressesthe mixture to a pressure higher than the supply pressure and the checkvalve 28 closes. This energizes the ignition circuit and the ignitionmeans 16 to explode the mixture, restarting the cycle.

As an operating example of the system of the present invention,reference is made to FIGS. 10, II and 12. Assuming the volume offuel/air mixture at the time of explosion in the explosion chamber(chamber 12 in FIG. I) to be 22 cubic feet and pressure thereof is 25psig (pounds per square inch gauge), and assuming the diameter of thederg exhaust conduit 24 (FIG. I) to be I6 inches and the length of thedreg exhaust conduit or outlet pipe to be 500 feet, FIG. 10 shows thevelocity (in feet per second) of the liquid in the dreg exhaust conduit24, FIG. 11 shows the pressure (in pounds per square inch absolute) inthe explosion or combustion chamber 12, and FIG. I2 shows the cumulativeliquid volume pumped for one cycle of the operation. The cycle beginswith filling of the chamber 12 with the compressed air/fuel mixture atpsig (approximately 40 psia). The filling occurs at a constant pressureand during this period the velocity of the dreg fluid or liq uid in thedreg exhaust conduit 24 increases from 5.4 to 9.4 feet per second. Afterl.5 seconds, 22 cubic feet of gas have entered the chamber I2 and thisgas mixture is exploded which causes a very fast pressure rise to 220psia. The velocity of the dreg fluid also increases, but less rapidlydue to the inertia of the slurry mass and friction of the pipe walls.The gas (exploding fuel mixture) expands as the dreg liquid leaves thechamber I2, until at 25 pisa (about It) psig) the exchamber pressurereturns to one atmosphere;

Immediately the chamber 12 begins filling with more dreg material underthe influence of gravity.

Since the liquid in the dreg exhaust conduit 24 still has a considerablevelocity due to the explosive forces earlier applied, the quantity ofdreg material entering the system through the check valve 22 is muchgreater than the volume of the chamber 12.

haust outlet means 38 (FIG. 3) is opened and the The "snag amassSissies.sseseaasamray which time velocity of the dreg material decaysdue to the friction forces at the conduit walls. When the chamber i2 isfilled with dreg material the cycle is ready to begin again. It shouldbe noted that the veloc ity of the dreg material never reaches zero andranges between the limits of 5.4 feet per second and 26 feet per second.The liquid pressure in the explosion chamber 12 varies from oneatmosphere to 220 psia.

FIG. 12 shows the cumulative flow of liquid whereby each cycle pumpsabout 1,200 gallons of dreg material in 8.8 seconds, or 8,200 gallonsper minute.

On the basis of the foregoing example, it is estimated that compressedair requirements are about 342 standard cubic feet per minute at 40 psiawhich would require about a 35 horsepower compressor drive to meet fuelrequirements of 0.34 gallons of gasoline per minute for operation of thesystem.

it will be recognized that the example set forth above illustrates onlyone of many possible combinations of gas volume, gas pressure andequipment size. Other parameters and equipment sizes may be employeddepending on the nature of the liquid to be pumped or dredged, thedistance the material is to be moved and the like.

The present invention, therefore, is well adapted to carry out theobjects and attain the ends and advantages mentioned as well as othersinherent therein. While a presently preferred embodiment of theinvention has been given for the purpose of disclosure, nu-

merous changes in the detail of construction and the combination, shape,size and arrangement of parts may be resorted to without departing fromthe spirit of the invention and the scope of the appended claims.

What is claimed is:

l. A dredging apparatus, comprising,

a. an explosion chamber having i. a fuel inlet supply means for forproviding an explosive mixture-of air and fuel intermittently to theexplosion chamber (a), said fuel inlet supply means (a) (i) comprising,

i. a fuel conduit in fluid communication with the upper interior portionof the explosion chamber (a),

2. a check valve within said fuel conduit to limit flow of fuelunidirectionally to the explosion chamber, and

3. a fuel source means in communication with the fuel conduit forproviding an explosive mixture of fuel sequentially to said fuelconduit,

ii. ignition means for exploding fuel within the explosion chamber (a)in timed relation 'with the fuel inlet supply means (a) (i), and

iii. an exhaust outlet means for removal of exhaust gases from theexplosion chamber (a),

b. a dreg intake conduit in fluid communication with the lower interiorportion of the explosion chamber c. check valve means within the intakeconduit (b) for limiting flow of fluid therethrough unidirectionally tothe explosion chamber (a),

d. an unrestricted dreg exhaust conduit in fluid communication with thelower interior portion of the explosion chamber (a). and

e. means coacting with the check valve (a) (i) (2) within the fuelconduit to sense closure of the 8 check valve (a) (i 2) and activate theignition means (a) (ii), closure of said check valve (a) (i) (2) withinsaid fuel conduit caused by pressure within said chamber.

v 2. The dredging apparatus of claim 1 wherein the exhaust means (a)(ii) comprises,

an exhaust gas conduit in fluid communication with the interior portionof the explosion chamber (a) at a point juxtaposed and above a planebetween 10 the dreg intake conduit (b) and the dreg exhaust conduit (d),and

a float valve means in said exhaust gas conduit for opening the exhaustconduit to the interior of the explosion chamber (a) to remove exhaustgases upon lowering the level of dregs within the chamber (a) and forclosing the exhaust gas conduit upon rising of the level of the dregswithin the restraining the ball member for releasable engagement withthe seat. -4. The dredging apparatus of claim 1 wherein the check valvemeans (c) within the intake conduit (b) comprises a grid member havingopenings therein and secured within the dreg intake conduit (b), and

an openable cover member secured against the side 5 of the grid memberfacing the explosion chamber 5: The dredging apparatus of claim 4including, additionally, v i

a grate secured within the dreg intake conduit (b) on 40 the side of thegrid member opposed from the explosion chamber (a), said grate havingopenings smaller than the openings within the grid member. 6. Thedredging apparatus of claim 1 whereinlthe dreg exhaust conduit (d) isY-shaped in configuration. tiara istasssamsiaaaaissg a. an explosionchamber having i. a fuel inlet supply means including a fuel conduit influid communication with the upper interior portion of the explosionchamber (a), a check valve within said fuel conduit to limit flow offuelunidirect'ionally to the explosion chamber, and a fuel source meansin communication with the fuel conduit for providing an explosivemixture of air and fuel sequentially to said conduit,

ii. ignition means for exploding fuel within the explosion chamber (a)in relation to pressure in said chamber, iii. means coacting with thecheck valve within the fuel conduit to sense closure of the check valveand activate the ignition means (a) (ii), and iv. an exhaust outletmeans including an exhaust conduit in fluid communication with theinterior portion of the explosion chamber (a), and a float valve meansin said exhaust gas conduit for opening the exhaust gas conduit to theinterior of the explosion chamber (a) to remove exhaust 'gasesiiponlowering'the level of dregs within the 9 10 chamber (a) and for closingthe exhaust gas con- The dredging apparatus of Claim 7 wherein the duitupon rising of the level of dregs within the float f means of thficXhaust Outlet means chamber (a), comprises, b; a dreg intake conduit influid communication with a ball member having buoyancy relative to thedregs the lower interior portion of the explosion chamber entering theexplosion Chamber (3) a seat affixed to the exhaust gas conduit withinthe c. check valve means within the intake conduit (b) XPt0Si0h Chamberand for limiting flow of fluid therethrough unidireca cage membersecured to said exhaust gas conduit tionally to the explosion chamber(a), said check restraining the ball member for releasableengagevalvemeans including ment with the seat.

i. a grid member secured within the dreg intake 9-The g g apparatusOfctaim 7 including, addiconduit (b), and n y,

ii. an openable cover member secured against the a grate Secured Withinthe g intake Conduit on side of the grid member facing the explosion theSide Of the g member PP m chamber (a), and 5 the explosion chamber (a),said grate having opend. a dreg exhaust conduit in fluid communicationings Smaller than the openings within the grid with the lower interiorportion of the explosion member chamber (a), the dreg exhaust conduit(d) and the dreg intake conduit (b) defining a plane above which isjuxtaposed the exhaust outlet means (a) UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 3,787,144 Dated January 22 1974Inventor(s) Charles D. Wood It is certi ied that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

I Change the address of the assignee from "Bexar, Tex. to -San Antonio,Tex.--

Column 1, line 10, cancel "U.S. Pat." and insert -the following UnitedStates Letters Patent:-

Column 2, line 40, cancel "thee" and insert -the- Column 4, lines 15 and18, cancel "Y" and insert --Y"-- 3 Column 5, line 45, cancel (IID 16)and insert 6 Column 5, line 47, cancel the equation shown and insert d DP (0) 0 Column 5, line 49, cancel the equation shown and insert 2 P 6 p)4 g Signed and sealed this 17th day of September 1974.

(SEAL) Attest: v

MCCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner ofPatents ORM PO-1OS0 mo es) USCOMM-DC 60376-969 u s covuuurm unmncarrlct. I!" o-Ju-ul UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3 787 144 Dated January 22 1974 lnventor(s)Charles D. Wood It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Change the address of the assignee from "Bexare, Tex." to -San Antonio,Tex.-- I

Column. 1, line 10, cancel "U.S. Pat." and insert -the following UnitedStates Letters ,Patent:-

Column 2, line 40, cancel "thee" and insert'-the- Column 4, lines 15 and18, cancel "Y" and insert "Y"- u 3 Column 5, line 45, cancel (HD l6) andinsert Column 5, line 47 cancel the equation shown and insert Column 5,line 49, cancel the equation shown and insert 3 2 p 6 (o) 1 4 9 P Signedand sealed this 17th day of September 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. 7 C. MARSHALL DANN Attesting Officer Commissioner ofPatents DRM PO-1OSO (10-69) I USCOMM-DC 6O376-P69 U 5. GOVERNMENTPRINTING OFFICE 9G9 O-36G33l

1. A dredging apparatus, comprising, a. an explosion chamber having i. afuel inlet supply means for for providing an explosive mixture of airand fuel intermittently to the explosion chamber (a), said fuel inletsupply means (a) (i) comprising,
 1. a fuel conduit in fluidcommunication with the upper interior portion of the explosion chamber(a),
 2. a check valve within said fuel conduit to limit flow of fuelunidirectionally to the explosion chamber, and
 3. a fuel source means incommunication with the fuel conduit for providing an explosive mixtureof fuel sequentially to said fuel conduit, ii. ignition means forexploding fuel within the explosion chamber (a) in timed relation withthe fuel inlet supply means (a) (i), and iii. an exhaust outlet meansfor removal of exhaust gases from the explosion chaMber (a), b. a dregintake conduit in fluid communication with the lower interior portion ofthe explosion chamber (a), c. check valve means within the intakeconduit (b) for limiting flow of fluid therethrough unidirectionally tothe explosion chamber (a), d. an unrestricted dreg exhaust conduit influid communication with the lower interior portion of the explosionchamber (a), and e. means coacting with the check valve (a) (i) (2)within the fuel conduit to sense closure of the check valve (a) (i) (2)and activate the ignition means (a) (ii), closure of said check valve(a) (i) (2) within said fuel conduit caused by pressure within saidchamber.
 2. a check valve within said fuel conduit to limit flow of fuelunidirectionally to the explosion chamber, and
 2. The dredging apparatusof claim 1 wherein the exhaust means (a) (ii) comprises, an exhaust gasconduit in fluid communication with the interior portion of theexplosion chamber (a) at a point juxtaposed and above a plane betweenthe dreg intake conduit (b) and the dreg exhaust conduit (d), and afloat valve means in said exhaust gas conduit for opening the exhaustconduit to the interior of the explosion chamber (a) to remove exhaustgases upon lowering the level of dregs within the chamber (a) and forclosing the exhaust gas conduit upon rising of the level of the dregswithin the chamber (a).
 3. The apparatus of claim 2 wherein the floatvalve means comprises, a ball member having buoyancy relative to thedregs entering the explosion chamber (a), a seat affixed to the end ofthe exhaust gas conduit within the exhaust chamber (a), and a cagemember secured to said exhaust gas conduit restraining the ball memberfor releasable engagement with the seat.
 3. a fuel source means incommunication with the fuel conduit for providing an explosive mixtureof fuel sequentially to said fuel conduit, ii. ignition means forexploding fuel within the explosion chamber (a) in timed relation withthe fuel inlet supply means (a) (i), and iii. an exhaust outlet meansfor removal of exhaust gases from the explosion chaMber (a), b. a dregintake conduit in fluid communication with the lower interior portion ofthe explosion chamber (a), c. check valve means within the intakeconduit (b) for limiting flow of fluid therethrough unidirectionally tothe explosion chamber (a), d. an unrestricted dreg exhaust conduit influid communication with the lower interior portion of the explosionchamber (a), and e. means coacting with the check valve (a) (i) (2)within the fuel conduit to sense closure of the check valve (a) (i) (2)and activate the ignition means (a) (ii), closure of said check valve(a) (i) (2) within said fuel conduit caused by pressure within saidchamber.
 4. The dredging apparatus of claim 1 wherein the check valvemeans (c) within the intake conduit (b) comprises a grid member havingopenings therein and secured within the dreg intake conduit (b), and anopenable cover member secured against the side of the grid member facingthe explosion chamber (a).
 5. The dredging apparatus of claim 4including, additionally, a grate secured within the dreg intake conduit(b) on the side of the grid member opposed from the explosion chamber(a), said grate having openings smaller than the openings within thegrid member.
 6. The dredging apparatus of claim 1 wherein the dregexhaust conduit (d) is Y-shaped in configuration.
 7. A dredgingapparatus, comprising a. an explosion chamber having i. a fuel inletsupply means including a fuel conduit in fluid communication with theupper interior portion of the explosion chamber (a), a check valvewithin said fuel conduit to limit flow of fuel unidirectionally to theexplosion chamber, and a fuel source means in communication with thefuel conduit for providing an explosive mixture of air and fuelsequentially to said conduit, ii. ignition means for exploding fuelwithin the explosion chamber (a) in relation to pressure in saidchamber, iii. means coacting with the check valve within the fuelconduit to sense closure of the check valve and activate the ignitionmeans (a) (ii), and iv. an exhaust outlet means including an exhaustconduit in fluid communication with the interior portion of theexplosion chamber (a), and a float valve means in said exhaust gasconduit for opening the exhaust gas conduit to the interior of theexplosion chamber (a) to remove exhaust gases upon lowering the level ofdregs within the chamber (a) and for closing the exhaust gas conduitupon rising of the level of dregs within the chamber (a), b. a dregintake conduit in fluid communication with the lower interior portion ofthe explosion chamber (a), c. check valve means within the intakeconduit (b) for limiting flow of fluid therethrough unidirectionally tothe explosion chamber (a), said check valve means including i. a gridmember secured within the dreg intake conduit (b), and ii. an openablecover member secured against the side of the grid member facing theexplosion chambeR (a), and d. a dreg exhaust conduit in fluidcommunication with the lower interior portion of the explosion chamber(a), the dreg exhaust conduit (d) and the dreg intake conduit (b)defining a plane above which is juxtaposed the exhaust outlet means (a)(iv).
 8. The dredging apparatus of claim 7 wherein the float valve meansof the exhaust outlet means (a) (iv) comprises, a ball member havingbuoyancy relative to the dregs entering the explosion chamber (a), aseat affixed to the exhaust gas conduit within the explosion chamber(a), and a cage member secured to said exhaust gas conduit restrainingthe ball member for releasable engagement with the seat.
 9. The dredgingapparatus of claim 7 including, additionally, a grate secured within thedreg intake conduit (b) on the side of the grid member (c) (i) opposedfrom the explosion chamber (a), said grate having openings smaller thanthe openings within the grid member (c) (i).